Honda releases the first cogeneration system for home use in the world

Osaka Gas and many other natural gas utilities in Japan carry a product called ECOWILL(see note 1) in their line of home energy appliances. ECOWILL is a so-called household cogeneration system, an energy-efficient appliance that burns natural gas or liquefied petroleum gas to generate electricity and uses the leftover thermal energy from the engine to supply hot water and heat the home. Because they waste so little energy, ECOWILL appliances can save the average family of four roughly 50,000 yen (U.S.$535) annually on their utility bills (see note 2).

An ECOWILL appliance comprises two distinct systems: a cogeneration unit, which generates electricity and captures leftover heat, and a water heater, which delivers hot water to the home. Honda manufactures the cogeneration unit, which gas companies then combine with a water heater for sale as a complete system.

Kazuhiro Togawa, who worked for many years on development of the cogeneration unit as Chief Researcher at Honda R&D's Power Products R&D Center and LPL ("large project leader," the title given to development project leaders at Honda) of the project, described the reasoning behind commercialization of the cogeneration unit.

"Commercializing a home cogeneration system was an idea that Honda pitched to the gas companies. At that time, the only cogeneration systems were large-scale system used by factories and power plants; there was no such thing as a compact appliance for home use. So Honda used the know-how we had built through our power equipment business to develop a household cogeneration unit with a gas engine. In partnership with gas companies and water heater makers, in 2003 we delivered the world's first household gas-engine cogeneration system, the ECOWILL."

1: ECOWILL is a registered trademark of Osaka Gas Co., Ltd.
2: Compared to a condensing boiler that runs on city gas (13A) and electricity generated by a thermal power plant; based on gas industry data. Cost benefits fluctuate depending on how energy is used and on the price of gas and electricity.

MCHP1.0R, a household gas-engine cogeneration unit with autonomous operation capability for starting in power outages (right), and starting the unit with the recoil starter cord (left)

Adding autonomous operation capability after the earthquake

In November 2012, a new ECOWILL model came on the market with an autonomously operable cogeneration unit—the core component of the appliance—that could be used even in power outages.

Autonomous operation is a machine's ability to start and function without an external supply of electricity. The gas engines in previous cogeneration unit models, like automobile and other engines, started via a starter motor, which needs electricity to work. Since this electricity typically comes from the electric grid, the engine failed to start when the power went out. In other words, these models required an external electricity supply to start, even though the devices themselves generated electricity by burning natural gas. In contrast, the ECOWILL PLUS with autonomous operation capability is additionally equipped with what is called a recoil starter, a device with a cord that, when pulled, starts the engine without external electricity.

"We talked about adding autonomous operation capability back in 2003 when we released the first model," said Togawa. "In Japan, though, the probability of a blackout occurring is extremely low, so customers tended not to pay extra money for something they probably wouldn't use."

Everything changed after the Great East Japan Earthquake. The event reawakened in the Japanese public the understanding of just how dangerous it can be not to have electricity in an emergency, and just how important electricity is for keeping oneself and one's family alive. Consumers expressed the need for a home cogeneration system that would safeguard them against power outages. In response, Honda immediately picked up the discussion about autonomous operation and proposed the idea to gas companies.

Recoil starters are a common feature on electric generators, outboard engines, and other small machines. They may seem easy to develop, but Masanori Takeishi, researcher at the Power Products R&D Center, thought quite the contrary.

"The cogeneration unit itself underwent dramatic downsizing in the new model released in 2011. So there was no space left to fit anything. The trouble we had was developing a much smaller recoil starter and then prying open enough space to fit it. Also, because the recoil starter would only be used in a power outage, it had to work, otherwise there would be no point in installing it. We conducted a number of tests and made sure the specifications were such that users of all genders, ages, and body types could start the engine." The new model with autonomous operation capability deeply resonated with consumers and has attracted more inquiries at gas companies than conventional models.